Methods of manufacturing semiconductor devices

ABSTRACT

A semiconductor device and method of making a conductive connector is provided. In an embodiment an opening is formed within a photoresist by adjusting the center point of an in-focus area during the exposure process. Once the photoresist has been developed to form an opening, an after development baking process is utilized to reshape the opening. Once reshaped, a conductive material is formed into the opening to take on the shape of the opening.

PRIORITY CLAIM AND CROSS-REFERENCE

This application claims priority to and the benefit of U.S. ProvisionalApplication No. 62/691,878, filed on Jun. 29, 2018, and entitled“Semiconductor Device and Method of Manufacture,” which application isincorporated herein by reference.

BACKGROUND

The semiconductor industry has experienced rapid growth due tocontinuous improvements in the integration density of a variety ofelectronic components (e.g., transistors, diodes, resistors, capacitors,etc.). For the most part, this improvement in integration density hascome from repeated reductions in minimum feature size (e.g., shrinkingthe semiconductor process node towards the sub-20 nm node), which allowsmore components to be integrated into a given area. As the demand forminiaturization, higher speed and greater bandwidth, as well as lowerpower consumption and latency has grown recently, there has grown a needfor smaller and more creative packaging techniques of semiconductordies.

As semiconductor technologies further advance, stacked and bondedsemiconductor devices have emerged as an effective alternative tofurther reduce the physical size of a semiconductor device. In a stackedsemiconductor device, active circuits such as logic, memory, processorcircuits and the like are fabricated at least partially on separatesubstrates and then physically and electrically bonded together in orderto form a functional device. Such bonding processes utilizesophisticated techniques, and improvements are desired.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 illustrates a formation of through interposer vias in accordancewith some embodiments.

FIG. 2 illustrates a semiconductor device in accordance with someembodiments.

FIG. 3 illustrates a placement of the semiconductor device in accordancewith some embodiments.

FIG. 4 illustrates an encapsulant of the through interposer vias and thesemiconductor device in accordance with some embodiments.

FIG. 5 illustrates a placement of a photoresist in accordance with someembodiments.

FIGS. 6A-6D illustrate an exposure of the photoresist in accordance withsome embodiments.

FIGS. 7A-7B illustrate a development of the photoresist in accordancewith some embodiments.

FIG. 8 illustrates a post-development annealing process in accordancewith some embodiments.

FIG. 9 illustrates a formation of an external connection in accordancewith some embodiments.

FIG. 10 illustrates a patterning of a seed layer in accordance with someembodiments.

FIG. 11 illustrates a formation of conductive bumps on the externalconnection in accordance with some embodiments.

FIG. 12 illustrates a debonding of the carrier wafer in accordance withsome embodiments.

FIG. 13 illustrates a bonding of a second package in accordance withsome embodiments.

FIG. 14 illustrates a singulation in accordance with some embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the invention. Specificexamples of components and arrangements are described below to simplifythe present disclosure. These are, of course, merely examples and arenot intended to be limiting. For example, the formation of a firstfeature over or on a second feature in the description that follows mayinclude embodiments in which the first and second features are formed indirect contact, and may also include embodiments in which additionalfeatures may be formed between the first and second features, such thatthe first and second features may not be in direct contact. In addition,the present disclosure may repeat reference numerals and/or letters inthe various examples. This repetition is for the purpose of simplicityand clarity and does not in itself dictate a relationship between thevarious embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

With reference now to FIG. 1, there is shown a carrier substrate 101with an adhesive layer 103, a polymer layer 105, and a first seed layer107 over the carrier substrate 101. The carrier substrate 101 comprises,for example, silicon based materials, such as glass or silicon oxide, orother materials, such as aluminum oxide, combinations of any of thesematerials, or the like. The carrier substrate 101 is planar in order toaccommodate an attachment of semiconductor devices such as a firstsemiconductor device 201 and a second semiconductor device 301 (notillustrated in FIG. 1 but illustrated and discussed below with respectto FIGS. 2-3).

The adhesive layer 103 is placed on the carrier substrate 101 in orderto assist in the adherence of overlying structures (e.g., the polymerlayer 105). In an embodiment the adhesive layer 103 may comprise anultra-violet glue, which loses its adhesive properties when exposed toultra-violet light. However, other types of adhesives, such as pressuresensitive adhesives, radiation curable adhesives, epoxies, combinationsof these, or the like, may also be used. The adhesive layer 103 may beplaced onto the carrier substrate 101 in a semi-liquid or gel form,which is readily deformable under pressure.

The polymer layer 105 is placed over the adhesive layer 103 and isutilized in order to provide protection to, e.g., the firstsemiconductor device 201 and the second semiconductor device 301 oncethe first semiconductor device 201 and the second semiconductor device301 have been attached. In an embodiment the polymer layer 105 may bepolybenzoxazole (PBO), although any suitable material, such as polyimideor a polyimide derivative, Solder Resistance (SR), or Ajinomoto build-upfilm (ABF) may be utilized. The polymer layer 105 may be placed using,e.g., a spin-coating process to a thickness of between about 2 μm andabout 15 μm, such as about 5 μm, although any suitable method andthickness may be used.

The first seed layer 107 is formed over the polymer layer 105. In anembodiment the first seed layer 107 is a thin layer of a conductivematerial that aids in the formation of a thicker layer during subsequentprocessing steps. The first seed layer 107 may comprise a layer oftitanium about 1,000 Å thick followed by a layer of copper about 5,000 Åthick. The first seed layer 107 may be created using processes such assputtering, evaporation, or PECVD processes, depending upon the desiredmaterials. The first seed layer 107 may be formed to have a thickness ofbetween about 0.3 μm and about 1 μm, such as about 0.5 μm.

FIG. 1 also illustrates a placement and patterning of a photoresist 109over the first seed layer 107. In an embodiment the photoresist 109 maybe placed on the first seed layer 107 using, e.g., a spin coatingtechnique to a height of between about 50 μm and about 250 μm, such asabout 120 μm. Once in place, the photoresist 109 may then be patternedby exposing the photoresist 109 to a patterned energy source (e.g., apatterned light source) so as to induce a chemical reaction, therebyinducing a physical change in those portions of the photoresist 109exposed to the patterned light source. A developer is then applied tothe exposed photoresist 109 to take advantage of the physical changesand selectively remove either the exposed portion of the photoresist 109or the unexposed portion of the photoresist 109, depending upon thedesired pattern.

In an embodiment the pattern formed into the photoresist 109 is apattern for vias 111. The vias 111 are formed in such a placement as tobe located on different sides of subsequently attached devices such asthe first semiconductor device 201 and the second semiconductor device301. However, any suitable arrangement for the pattern of vias 111, suchas by being located such that the first semiconductor device 201 and thesecond semiconductor device 301 are placed on opposing sides of the vias111, may be utilized.

In an embodiment the vias 111 are formed within the photoresist 109. Inan embodiment the vias 111 comprise one or more conductive materials,such as copper, tungsten, other conductive metals, or the like, and maybe formed, for example, by electroplating, electroless plating, or thelike. In an embodiment, an electroplating process is used wherein thefirst seed layer 107 and the photoresist 109 are submerged or immersedin an electroplating solution. The first seed layer 107 surface iselectrically connected to the negative side of an external DC powersupply such that the first seed layer 107 functions as the cathode inthe electroplating process. A solid conductive anode, such as a copperanode, is also immersed in the solution and is attached to the positiveside of the power supply. The atoms from the anode are dissolved intothe solution, from which the cathode, e.g., the first seed layer 107,acquires the dissolved atoms, thereby plating the exposed conductiveareas of the first seed layer 107 within the opening of the photoresist109.

Once the vias 111 have been formed using the photoresist 109 and thefirst seed layer 107, the photoresist 109 may be removed using asuitable removal process (not illustrated in FIG. 1 but seen in FIG. 3below). In an embodiment, a plasma ashing process may be used to removethe photoresist 109, whereby the temperature of the photoresist 109 maybe increased until the photoresist 109 experiences a thermaldecomposition and may be removed. However, any other suitable process,such as a wet strip, may be utilized. The removal of the photoresist 109may expose the underlying portions of the first seed layer 107.

Once exposed a removal of the exposed portions of the first seed layer107 may be performed (not illustrated in FIG. 1 but seen in FIG. 3below). In an embodiment the exposed portions of the first seed layer107 (e.g., those portions that are not covered by the vias 111) may beremoved by, for example, a wet or dry etching process. For example, in adry etching process reactants may be directed towards the first seedlayer 107 using the vias 111 as masks. In another embodiment, etchantsmay be sprayed or otherwise put into contact with the first seed layer107 in order to remove the exposed portions of the first seed layer 107.After the exposed portion of the first seed layer 107 has been etchedaway, a portion of the polymer layer 105 is exposed between the vias111.

FIG. 2 illustrates a first semiconductor device 201 that will beattached to the polymer layer 105 within the vias 111 (not illustratedin FIG. 2 but illustrated and described below with respect to FIG. 3).In an embodiment the first semiconductor device 201 comprises a firstsubstrate 203, first active devices (not individually illustrated),first metallization layers 205, first contact pads 207, a firstpassivation layer 211, and first external connectors 209. The firstsubstrate 203 may comprise bulk silicon, doped or undoped, or an activelayer of a silicon-on-insulator (SOI) substrate. Generally, an SOIsubstrate comprises a layer of a semiconductor material such as silicon,germanium, silicon germanium, SOI, silicon germanium on insulator(SGOI), or combinations thereof. Other substrates that may be usedinclude multi-layered substrates, gradient substrates, or hybridorientation substrates.

The first active devices comprise a wide variety of active devices andpassive devices such as capacitors, resistors, inductors and the likethat may be used to generate the desired structural and functionaldesires of the design for the first semiconductor device 201. The firstactive devices may be formed using any suitable methods either within orelse on the first substrate 203.

The first metallization layers 205 are formed over the first substrate203 and the first active devices and are designed to connect the variousactive devices to form functional circuitry. In an embodiment the firstmetallization layers 205 are formed of alternating layers of dielectricand conductive material and may be formed through any suitable process(such as deposition, damascene, dual damascene, etc.). In an embodimentthere may be four layers of metallization separated from the firstsubstrate 203 by at least one interlayer dielectric layer (ILD), but theprecise number of first metallization layers 205 is dependent upon thedesign of the first semiconductor device 201.

The first contact pads 207 may be formed over and in electrical contactwith the first metallization layers 205. The first contact pads 207 maycomprise aluminum, but other materials, such as copper, may be used. Thefirst contact pads 207 may be formed using a deposition process, such assputtering, to form a layer of material (not shown) and portions of thelayer of material may then be removed through a suitable process (suchas photolithographic masking and etching) to form the first contact pads207. However, any other suitable process may be utilized to form thefirst contact pads 207. The first contact pads 207 may be formed to havea thickness of between about 0.5 μm and about 4 μm, such as about 1.45μm.

The first passivation layer 211 may be formed on the first substrate 203over the first metallization layers 205 and the first contact pads 207.The first passivation layer 211 may be made of one or more suitabledielectric materials such as silicon oxide, silicon nitride, low-kdielectrics such as carbon doped oxides, extremely low-k dielectricssuch as porous carbon doped silicon dioxide, combinations of these, orthe like. The first passivation layer 211 may be formed through aprocess such as chemical vapor deposition (CVD), although any suitableprocess may be utilized, and may have a thickness between about 0.5 μmand about 5 μm, such as about 9.25 KÅ.

The first external connectors 209 may be formed to provide conductiveregions for contact between the first contact pads 207 and, e.g., afirst redistribution layer 501 (not illustrated in FIG. 2 butillustrated and described below with respect to FIG. 5). In anembodiment the first external connectors 209 may be conductive pillarsand may be formed by initially forming a photoresist (not shown) overthe first passivation layer 211 to a thickness between about 5 μm toabout 20 μm, such as about 10 μm. The photoresist may be patterned toexpose portions of the first passivation layers through which theconductive pillars will extend. Once patterned, the photoresist may thenbe used as a mask to remove the desired portions of the firstpassivation layer 211, thereby exposing those portions of the underlyingfirst contact pads 207 to which the first external connectors 209 willmake contact.

The first external connectors 209 may be formed within the openings ofboth the first passivation layer 211 and the photoresist. The firstexternal connectors 209 may be formed from a conductive material such ascopper, although other conductive materials such as nickel, gold, ormetal alloy, combinations of these, or the like may also be used.Additionally, the first external connectors 209 may be formed using aprocess such as electroplating, by which an electric current is runthrough the conductive portions of the first contact pads 207 to whichthe first external connectors 209 are desired to be formed, and thefirst contact pads 207 are immersed in a solution. The solution and theelectric current deposit, e.g., copper, within the openings in order tofill and/or overfill the openings of the photoresist and the firstpassivation layer 211, thereby forming the first external connectors209. Excess conductive material and photoresist outside of the openingsof the first passivation layer 211 may then be removed using, forexample, an ashing process, a chemical mechanical polish (CMP) process,combinations of these, or the like.

However, as one of ordinary skill in the art will recognize, the abovedescribed process to form the first external connectors 209 is merelyone such description, and is not meant to limit the embodiments to thisexact process. Rather, the described process is intended to be merelyillustrative, as any suitable process for forming the first externalconnectors 209 may be utilized. All suitable processes are fullyintended to be included within the scope of the present embodiments.

On an opposite side of the first substrate 203 than the firstmetallization layers 205, a die attach film (DAF) 213 may be formed inorder to assist in the attachment of the first semiconductor device 201to the polymer layer 105. In an embodiment the die attach film 213 is anepoxy resin, a phenol resin, acrylic rubber, silica filler, or acombination thereof, and is applied using a lamination technique.However, any other suitable material and method of formation may beutilized.

FIG. 3 illustrates a placement of the first semiconductor device 201onto the polymer layer 105 along with a placement of a secondsemiconductor device 301. In an embodiment the second semiconductordevice 301 may comprise a second substrate 303, second active devices(not individually illustrated), second metallization layers 305, secondcontact pads 307, a second passivation layer 311, and second externalconnectors 309. In an embodiment the second substrate 303, the secondactive devices, the second metallization layers 305, the second contactpads 307, the second passivation layer 311, and the second externalconnectors 309 may be similar to the first substrate 203, the firstactive devices, the first metallization layers 205, the first contactpads 207, the first passivation layer 211, and the first externalconnectors 209, although they may also be different.

In an embodiment the first semiconductor device 201 and the secondsemiconductor device 301 may be placed onto the polymer layer 105 using,e.g., a pick and place process. However, any other method of placing thefirst semiconductor device 201 and the second semiconductor device 301may be used.

FIG. 4 illustrates an encapsulation of the vias 111, the firstsemiconductor device 201 and the second semiconductor device 301. Theencapsulation may be performed in a molding device (not individuallyillustrated in FIG. 4), which may comprise a top molding portion and abottom molding portion separable from the top molding portion. When thetop molding portion is lowered to be adjacent to the bottom moldingportion, a molding cavity may be formed for the carrier substrate 101,the vias 111, the first semiconductor device 201, and the secondsemiconductor device 301.

During the encapsulation process the top molding portion may be placedadjacent to the bottom molding portion, thereby enclosing the carriersubstrate 101, the vias 111, the first semiconductor device 201, and thesecond semiconductor device 301 within the molding cavity. Onceenclosed, the top molding portion and the bottom molding portion mayform an airtight seal in order to control the influx and outflux ofgasses from the molding cavity. Once sealed, an encapsulant 401 may beplaced within the molding cavity. The encapsulant 401 may be a moldingcompound resin such as polyimide, PPS, PEEK, PES, a heat resistantcrystal resin, combinations of these, or the like. The encapsulant 401may be placed within the molding cavity prior to the alignment of thetop molding portion and the bottom molding portion, or else may beinjected into the molding cavity through an injection port.

Once the encapsulant 401 has been placed into the molding cavity suchthat the encapsulant 401 encapsulates the carrier substrate 101, thevias 111, the first semiconductor device 201, and the secondsemiconductor device 301, the encapsulant 401 may be cured in order toharden the encapsulant 401 for optimum protection. While the exactcuring process is dependent at least in part on the particular materialchosen for the encapsulant 401, in an embodiment in which moldingcompound is chosen as the encapsulant 401, the curing could occurthrough a process such as heating the encapsulant 401 to between about100° C. and about 130° C., such as about 125° C. for about 60 sec toabout 3000 sec, such as about 600 sec. Additionally, initiators and/orcatalysts may be included within the encapsulant 401 to better controlthe curing process.

However, as one having ordinary skill in the art will recognize, thecuring process described above is merely an exemplary process and is notmeant to limit the current embodiments. Other curing processes, such asirradiation or even allowing the encapsulant 401 to harden at ambienttemperature, may be used. Any suitable curing process may be used, andall such processes are fully intended to be included within the scope ofthe embodiments discussed herein.

FIG. 4 also illustrates a thinning of the encapsulant 401 in order toexpose the vias 111, the first semiconductor device 201, and the secondsemiconductor device 301 for further processing. The thinning may beperformed, e.g., using a mechanical grinding or chemical mechanicalpolishing (CMP) process whereby chemical etchants and abrasives areutilized to react and grind away the encapsulant 401, the firstsemiconductor device 201 and the second semiconductor device 301 untilthe vias 111, the first external connectors 209 (on the firstsemiconductor device 201), and the second external connectors 309 (onthe second semiconductor device 301) have been exposed. As such, thefirst semiconductor device 201, the second semiconductor device 301, andthe vias 111 may have a planar surface that is also coplanar with theencapsulant 401.

However, while the CMP process described above is presented as oneillustrative embodiment, it is not intended to be limiting to theembodiments. Any other suitable removal process may be used to thin theencapsulant 401, the first semiconductor device 201, and the secondsemiconductor device 301 and expose the vias 111. For example, a seriesof chemical etches may be utilized. This process and any other suitableprocess may be utilized to thin the encapsulant 401, the firstsemiconductor device 201, and the second semiconductor device 301, andall such processes are fully intended to be included within the scope ofthe embodiments.

Optionally, after the encapsulant 401 has been thinned, the vias 111,the first external connectors 209, and the second external connectors309 may be recessed within the encapsulant 401. In an embodiment thevias 111, the first external connectors 209, and the second externalconnectors 309 may be recessed using, e.g., an etching process thatutilizes an etchant that is selective to the material of the vias 111,the first external connectors 209, and the second external connectors309 (e.g., copper). The vias 111, the first external connectors 209, andthe second external connectors 309 may be recessed to a depth of betweenabout 20 μm and about 300 μm, such as about 180 μm.

FIG. 5 illustrates cross-sectional views of a formation of a firstredistribution layer (RDL) 501, a second redistribution layer 505, and athird redistribution layer 509 in order to interconnect the firstsemiconductor device 201, the second semiconductor device 301, and thevias 111. In an embodiment the first redistribution layer 501 may beformed by initially forming a seed layer (not shown) of a titaniumcopper alloy through a suitable formation process such as CVD orsputtering. A photoresist (also not shown) may then be formed to coverthe seed layer, and the photoresist may then be patterned to exposethose portions of the seed layer that are located where the firstredistribution layer 501 is desired to be located.

Once the photoresist has been formed and patterned, a conductivematerial, such as copper, may be formed on the seed layer through adeposition process such as plating. The conductive material may beformed to have a thickness of between about 1 μm and about 10 μm, suchas about 5 μm. However, while the material and methods discussed aresuitable to form the conductive material, these materials are merelyexemplary. Any other suitable materials, such as AlCu or Au, and anyother suitable processes of formation, such as CVD or PVD, may be usedto form the first redistribution layer 501.

Once the conductive material has been formed, the photoresist may beremoved through a suitable removal process such as ashing. Additionally,after the removal of the photoresist, those portions of the seed layerthat were covered by the photoresist may be removed through, forexample, a suitable etch process using the conductive material as amask.

FIG. 5 also illustrates a formation of a third passivation layer 503over the first redistribution layer 501 in order to provide protectionand isolation for the first redistribution layer 501 and the otherunderlying structures. In an embodiment the third passivation layer 503may be polybenzoxazole (PBO), although any suitable material, such aspolyimide or a polyimide derivative, may be utilized. The thirdpassivation layer 503 may be placed using, e.g., a spin-coating processto a thickness of between about 5 μm and about 25 μm, such as about 7μm, although any suitable method and thickness may be used.

After the third passivation layer 503 has been formed, first openings504 (only one of which is illustrated in FIG. 5 for clarity) may be madethrough the third passivation layer 503 by removing portions of thethird passivation layer 503 to expose at least a portion of theunderlying first redistribution layer 501. The first openings 504 allowsfor contact between the first redistribution layer 501 and a secondredistribution layer 505 (described further below). The first openings504 may be formed using a suitable photolithographic mask and etchingprocess, although any suitable process to expose portions of firstredistribution layer 501 may be used.

The second redistribution layer 505 may be formed to provide additionalrouting and connectivity and in electrical connection with the firstredistribution layer 501. In an embodiment the second redistributionlayer 505 may be formed similar to the first redistribution layer 501.For example, a seed layer may be formed, a photoresist may be placed andpatterned on top of the seed layer, and conductive material may beplated into the patterned openings through the photoresist. Once formed,the photoresist may be removed, the underlying seed layer may be etched,the second redistribution layer 505 may be covered by a fourthpassivation layer 507 (which may be similar to the third passivationlayer 503), and the fourth passivation layer 507 may be patterned toform second openings 506 (only one of which is illustrated in FIG. 5 forclarity) and expose an underlying conductive portion of the secondredistribution layer 505.

The third redistribution layer 509 may be formed to provide additionalrouting along with electrical connection to the second redistributionlayer 505. In an embodiment the third redistribution layer 509 may beformed using materials and processes similar to the first redistributionlayer 501. For example, a seed layer may be formed, a photoresist may beplaced and patterned on top of the seed layer in a desired pattern forthe third redistribution layer 509, conductive material is plated intothe patterned openings of the photoresist, the photoresist is removed,and the seed layer is etched.

However, in addition to simply rerouting the electrical connections(similar to the second redistribution layer 505), the thirdredistribution layer 509 may also comprise a landing pad that will beutilized to form an electrical connection to, e.g., an overlying thirdexternal connection 901 (described further below). The landing pad maybe shaped in order to make suitable physical and electrical connectionwith the third external connection 901.

Once the third redistribution layer 509 has been formed, the thirdredistribution layer 509 may be covered by a fifth passivation layer511. The fifth passivation layer 511, similar to the third passivationlayer 503, may be formed from a polymer such as PBO, or may be formed ofa similar material as the third passivation layer 503 (e.g., polyimideor a polyimide derivative). The fifth passivation layer 511 may beformed to have a thickness of between about 2 μm and about 15 μm, suchas about 5 μm.

Once in place over the third redistribution layer 509, the fifthpassivation layer 511 may be planarized with the third redistributionlayer 509. In an embodiment the planarization may be performed using,e.g., a chemical mechanical polishing process, whereby etchants andabrasives are utilized along with a rotating platen in order tochemically and mechanically remove portions of the fifth passivationlayer 511 until the fifth passivation layer 511 is coplanar with thethird redistribution layer 509. However, any suitable planarizationprocess, such as a series of one or more etches or a mechanical grindingprocess, may be utilized.

After the fifth passivation layer 511 has been formed and planarized, asixth passivation layer 513 may be placed and patterned over the fifthpassivation layer 511 and the third redistribution layer 509. In anembodiment the sixth passivation layer 513 may be a similar material asthe fifth passivation layer 511 (e.g., PBO) and the sixth passivationlayer 513 may be patterned in order to expose an underlying portion ofthe third redistribution layer 509. In an embodiment the sixthpassivation layer 513 may be patterned using a photolithographic maskingand etching process, whereby a photoresist is deposited and patternedand then used as a mask during an etching process in order to removeportions of the sixth passivation layer 513 and expose portions of thethird redistribution layer 509. However, any suitable method ofpatterning the sixth passivation layer 513 may be utilized.

After the sixth passivation layer 513 has been formed and patterned, asecond seed layer 515 is deposited over the sixth passivation layer 513.In an embodiment the second seed layer 515 is a thin layer of aconductive material that aids in the formation of a thicker layer duringsubsequent processing steps. The second seed layer 515 may comprise alayer of titanium about 1,000 Å thick followed by a layer of copperabout 5,000 Å thick. The second seed layer 515 may be created usingprocesses such as sputtering, evaporation, or PECVD processes, dependingupon the desired materials. The second seed layer 515 may be formed tohave a thickness of between about 0.3 μm and about 1 μm, such as about0.5 μm.

Once the second seed layer 515 has been deposited, a photoresist 517 maybe placed onto the second seed layer 515 to prepare for a formation ofthe third external connection 901. In an embodiment the photoresist 517includes a photoresist polymer resin along with one or more photoactivecompounds (PACs) in a photoresist solvent. In an embodiment thephotoresist polymer resin may comprise a hydrocarbon structure (such asan alicyclic hydrocarbon structure) that contains one or more groupsthat will decompose (e.g., an acid labile group) or otherwise react whenmixed with acids, bases, or free radicals generated by the PACs (asfurther described below with respect to FIG. 6A). In an embodiment thehydrocarbon structure comprises a repeating unit that forms a skeletalbackbone of the photoresist polymer resin. This repeating unit mayinclude acrylic esters, methacrylic esters, crotonic esters, vinylesters, maleic diesters, fumaric diesters, itaconic diesters,(meth)acrylonitrile, (meth)acrylamides, styrenes, vinyl ethers,combinations of these, or the like.

Specific structures which may be utilized for the repeating unit of thehydrocarbon structure include methyl acrylate, ethyl acrylate, n-propylacrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate,tert-butyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate,acetoxyethyl acrylate, phenyl acrylate, 2-hydroxyethyl acrylate,2-methoxyethyl acrylate, 2-ethoxyethyl acrylate,2-(2-methoxyethoxy)ethyl acrylate, cyclohexyl acrylate, benzyl acrylate,2-alkyl-2-adamantyl (meth)acrylate or dialkyl(1-adamantyl)methyl(meth)acrylate, methyl methacrylate, ethyl methacrylate, n-propylmethacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutylmethacrylate, tert-butyl methacrylate, n-hexyl methacrylate,2-ethylhexyl methacrylate, acetoxyethyl methacrylate, phenylmethacrylate, 2-hydroxyethyl methacrylate, 2-methoxyethyl methacrylate,2-ethoxyethyl methacrylate, 2-(2-methoxyethoxy)ethyl methacrylate,cyclohexyl methacrylate, benzyl methacrylate, 3-chloro-2-hydroxypropylmethacrylate, 3-acetoxy-2-hydroxypropyl methacrylate,3-chloroacetoxy-2-hydroxypropyl methacrylate, butyl crotonate, hexylcrotonate and the like. Examples of the vinyl esters include vinylacetate, vinyl propionate, vinyl butylate, vinyl methoxyacetate, vinylbenzoate, dimethyl maleate, diethyl maleate, dibutyl maleate, dimethylfumarate, diethyl fumarate, dibutyl fumarate, dimethyl itaconate,diethyl itaconate, dibutyl itaconate, acrylamide, methyl acrylamide,ethyl acrylamide, propyl acrylamide, n-butyl acrylamide, tert-butylacrylamide, cyclohexyl acrylamide, 2-methoxyethyl acrylamide, dimethylacrylamide, diethyl acrylamide, phenyl acrylamide, benzyl acrylamide,methacrylamide, methyl methacrylamide, ethyl methacrylamide, propylmethacrylamide, n-butyl methacrylamide, tert-butyl methacrylamide,cyclohexyl methacrylamide, 2-methoxyethyl methacrylamide, dimethylmethacrylamide, diethyl methacrylamide, phenyl methacrylamide, benzylmethacrylamide, methyl vinyl ether, butyl vinyl ether, hexyl vinylether, methoxyethyl vinyl ether, dimethylaminoethyl vinyl ether and thelike. Examples of the styrenes include styrene, methyl styrene, dimethylstyrene, trimethyl styrene, ethyl styrene, isopropyl styrene, butylstyrene, methoxy styrene, butoxy styrene, acetoxy styrene, chlorostyrene, dichloro styrene, bromo styrene, vinyl methyl benzoate,α-methyl styrene, maleimide, vinylpyridine, vinylpyrrolidone,vinylcarbazole, combinations of these, or the like.

In an embodiment the repeating unit of the hydrocarbon structure mayalso have either a monocyclic or a polycyclic hydrocarbon structuresubstituted into it, or else the monocyclic or polycyclic hydrocarbonstructure may be the repeating unit, in order to form an alicyclichydrocarbon structure. Specific examples of monocyclic structures thatmay be used include bicycloalkane, tricycloalkane, tetracycloalkane,cyclopentane, cyclohexane, or the like. Specific examples of polycyclicstructures that may be used include adamantine, norbornane, isobornane,tricyclodecane, tetracycododecane, or the like.

The group which will decompose, otherwise known as a leaving group or,in an embodiment in which the PAC is a photoacid generator, an acidlabile group, is attached to the hydrocarbon structure so that it willreact with the acids/bases/free radicals generated by the PACs duringexposure. In an embodiment the group which will decompose may be acarboxylic acid group, a fluorinated alcohol group, a phenolic alcoholgroup, a sulfonic group, a sulfonamide group, a sulfonylimido group, an(alkylsulfonyl) (alkylcarbonyl)methylene group, an(alkylsulfonyl)(alkyl-carbonyl)imido group, abis(alkylcarbonyl)methylene group, a bis(alkylcarbonyl)imido group, abis(alkylsylfonyl)methylene group, a bis(alkylsulfonyl)imido group, atris(alkylcarbonyl methylene group, a tris(alkylsulfonyl)methylenegroup, combinations of these, or the like. Specific groups that may beutilized for the fluorinated alcohol group include fluorinatedhydroxyalkyl groups, such as a hexafluoroisopropanol group. Specificgroups that may be utilized for the carboxylic acid group includeacrylic acid groups, methacrylic acid groups, or the like.

In an embodiment the photoresist polymer resin may also comprise othergroups attached to the hydrocarbon structure that help to improve avariety of properties of the polymerizable resin. For example, inclusionof a lactone group to the hydrocarbon structure assists to reduce theamount of line edge roughness after the photoresist 517 has beendeveloped, thereby helping to reduce the number of defects that occurduring development. In an embodiment the lactone groups may includerings having five to seven members, although any suitable lactonestructure may be used for the lactone group.

The photoresist polymer resin may also comprise groups that can assistin increasing the adhesiveness of the photoresist 517 to underlyingstructures. In an embodiment polar groups may be used to help increasethe adhesiveness, and polar groups that may be used in this embodimentinclude hydroxyl groups, cyano groups, or the like, although anysuitable polar group may be utilized.

Optionally, the photoresist polymer resin may further comprise one ormore alicyclic hydrocarbon structures that do not also contain a groupwhich will decompose. In an embodiment the hydrocarbon structure thatdoes not contain a group which will decompose may include structuressuch as 1-adamantyl(meth)acrylate, tricyclodecanyl (meth)acrylate,cyclohexayl (methacrylate), combinations of these, or the like.

Additionally, the photoresist 517 also comprises one or more PACs. ThePACs may be photoactive components such as photoacid generators,photobase generators, free-radical generators, or the like, and the PACsmay be positive-acting or negative-acting. In an embodiment in which thePACs are a photoacid generator, the PACs may comprise halogenatedtriazines, onium salts, diazonium salts, aromatic diazonium salts,phosphonium salts, sulfonium salts, iodonium salts, imide sulfonate,oxime sulfonate, diazodisulfone, disulfone, o-nitrobenzylsulfonate,sulfonated esters, halogenerated sulfonyloxy dicarboximides,diazodisulfones, α-cyanooxyamine-sulfonates, imidesulfonates,ketodiazosulfones, sulfonyldiazoesters, 1,2-di(arylsulfonyl)hydrazines,nitrobenzyl esters, and the s-triazine derivatives, suitablecombinations of these, and the like.

Specific examples of photoacid generators that may be used includeα-(trifluoromethylsulfonyloxy)-bicyclo[2.2.1]hept-5-ene-2,3-dicarbo-ximide(MDT), N-hydroxy-naphthalimide (DDSN), benzoin tosylate,t-butylphenyl-α-(p-toluenesulfonyloxy)-acetate andt-butyl-α-(p-toluenesulfonyloxy)-acetate, triarylsulfonium anddiaryliodonium hexafluoroantimonates, hexafluoroarsenates,trifluoromethanesulfonates, iodonium perfluorooctanesulfonate,N-camphorsulfonyloxynaphthalimide,N-pentafluorophenylsulfonyloxynaphthalimide, ionic iodonium sulfonatessuch as diaryl iodonium (alkyl or aryl) sulfonate andbis-(di-t-butylphenyl)iodonium camphanylsulfonate,perfluoroalkanesulfonates such as perfluoropentanesulfonate,perfluorooctanesulfonate, perfluoromethanesulfonate, aryl (e.g., phenylor benzyl) triflates such as triphenylsulfonium triflate orbis-(t-butylphenyl)iodonium triflate; pyrogallol derivatives (e.g.,trimesylate of pyrogallol), trifluoromethanesulfonate esters ofhydroxyimides, α,α′-bis-sulfonyl-diazomethanes, sulfonate esters ofnitro-substituted benzyl alcohols, naphthoquinone-4-diazides, alkyldisulfones, and the like.

In an embodiment in which the PACs are a free-radical generator, thePACs may comprise n-phenylglycine, aromatic ketones such asbenzophenone, N,N′-tetramethyl-4,4′-diaminobenzophenone,N,N′-tetraethyl-4,4′-diaminobenzophenone,4-methoxy-4′-dimethylaminobenzo-phenone,3,3′-dimethyl-4-methoxybenzophenone,p,p′-bis(dimethylamino)benzo-phenone,p,p′-bis(diethylamino)-benzophenone, anthraquinone,2-ethylanthraquinone, naphthoquinone and phenanthraquinone, benzoinssuch as benzoin, benzoinmethylether, benzoinethylether,benzoinisopropylether, benzoin-n-butylether, benzoin-phenylether,methylbenzoin and ethybenzoin, benzyl derivatives such as dibenzyl,benzyldiphenyldisulfide and benzyldimethylketal, acridine derivativessuch as 9-phenylacridine and 1,7-bis(9-acridinyl)heptane, thioxanthonessuch as 2-chlorothioxanthone, 2-methylthioxanthone,2,4-diethylthioxanthone, 2,4-dimethylthioxanthone and2-isopropylthioxanthone, acetophenones such as 1,1-dichloroacetophenone,p-t-butyldichloro-acetophenone, 2,2-diethoxyacetophenone,2,2-dimethoxy-2-phenylacetophenone, and2,2-dichloro-4-phenoxyacetophenone, 2,4,5-triarylimidazole dimers suchas 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer,2-(o-chlorophenyl)-4,5-di-(m-methoxyphenyl imidazole dimer,2-(o-fluorophenyl)-4,5-diphenylimidazole dimer,2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer,2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer,2,4-di(p-methoxyphenyl)-5-phenylimidazole dimer,2-(2,4-dimethoxyphenyl)-4,5-diphenylimidazole dimer and2-(p-methylmercaptophenyl)-4,5-diphenylimidazole dimmer, suitablecombinations of these, or the like.

In an embodiment in which the PACs are a photobase generator, the PACsmay comprise quaternary ammonium dithiocarbamates, α aminoketones,oxime-urethane containing molecules such as dibenzophenoneoximehexamethylene diurethan, ammonium tetraorganylborate salts, andN-(2-nitrobenzyloxycarbonyl) cyclic amines, suitable combinations ofthese, or the like. However, as one of ordinary skill in the art willrecognize, the chemical compounds listed herein are merely intended asillustrated examples of the PACs and are not intended to limit theembodiments to only those PACs specifically described. Rather, anysuitable PAC may be utilized, and all such PACs are fully intended to beincluded within the scope of the present embodiments.

The individual components of the photoresist 517 may be placed into thephotoresist solvent in order to aid in the mixing and placement of thephotoresist 517. To aid in the mixing and placement of the photoresist517, the photoresist solvent is chosen at least in part based upon thematerials chosen for the photoresist polymer resin as well as the PACs.In particular, the photoresist solvent is chosen such that thephotoresist polymer resin and the PACs can be evenly dissolved into thephotoresist solvent and dispensed.

In an embodiment the photoresist solvent may be an organic solvent, andmay comprise any suitable solvent such as ketones, alcohols,polyalcohols, ethers, glycol ethers, cyclic ethers, aromatichydrocarbons, esters, propionates, lactates, lactic esters, alkyleneglycol monoalkyl ethers, alkyl lactates, alkyl alkoxypropionates, cycliclactones, monoketone compounds that contain a ring, alkylene carbonates,alkyl alkoxyacetate, alkyl pyruvates, lactate esters, ethylene glycolalkyl ether acetates, diethylene glycols, propylene glycol alkyl etheracetates, alkylene glycol alkyl ether esters, alkylene glycol monoalkylesters, or the like.

Specific examples of materials that may be used as the photoresistsolvent for the photoresist 517 include, acetone, methanol, ethanol,toluene, xylene, 4-hydroxy-4-methyl-2-pentatone, tetrahydrofuran, methylethyl ketone, cyclohexanone, methyl isoamyl ketone, 2-heptanone,ethylene glycol, ethylene glycol monoacetate, ethylene glycol dimethylether, ethylene glycol dimethyl ether, ethylene glycol methylethylether, ethylene glycol monoetheryl ether, methyl cellosolve acetate,ethyl cellosolve acetate, diethylene glycol, diethylene glycolmonoacetate, diethylene glycol monomethyl ether, diethylene glycoldiethyl ether, diethylene glycol dimethyl ether, diethylene glycolethylmethyl ether, dietherylene glycol monoethyl ether, diethyleneglycol monbutyl ether, ethyl 2-hydroxypropionate, methyl2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, ethylethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-2-methylbutanate,methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl acetate, butylacetate, methyl lactate and ethyl lactate, propylene glycol, propyleneglycol monoacetate, propylene glycol monoethyl ether acetate, propyleneglycol monomethyl ether acetate, propylene glycol monopropyl methylether acetate, propylene glycol monobutyl ether acetate, propyleneglycol monobutyl ether acetate, propylene glycol monomethyl etherpropionate, propylene glycol monoethyl ether propionate, propyleneglycol methyl ether acetate, propylene glycol ethyl ether acetate,ethylene glycol monomethyl ether acetate, ethylene glycol monoethylether acetate, propylene glycol monomethyl ether, propylene glycolmonoethyl ether, propylene glycol monopropyl ether, propylene glycolmonobutyl ether, ethylene glycol monomethyl ether, ethylene glycolmonoethyl ether, methyl lactate, ethyl lactate, propyl lactate, andbutyl lactate, ethyl 3-ethoxypropionate, methyl 3-methoxypropionate,methyl 3-ethoxypropionate, and ethyl 3-methoxypropionate,β-propiolactone, β-butyrolactone, γ-butyrolactone,α-methyl-γ-butyrolactone, β-methyl-γ-butyrolactone, γ-valerolactone,γ-caprolactone, γ-octanoic lactone, α-hydroxy-γ-butyrolactone,2-butanone, 3-methylbutanone, pinacolone, 2-pentanone, 3-pentanone,4-methyl-2-pentanone, 2-methyl-3-pentanone, 4,4-dimethyl-2-pentanone,2,4-dimethyl-3-pentanone, 2,2,4,4-tetramethyl-3-pentanone, 2-hexanone,3-hexanone, 5-methyl-3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone,2-methyl-3-heptanone, 5-methyl-3-heptanone, 2,6-dimethyl-4-heptanone,2-octanone, 3-octanone, 2-nonanone, 3-nonanone, 5-nonanone, 2-decanone,3-decanone, 4-decanone, 5-hexene-2-one, 3-pentene-2-one, cyclopentanone,2-methylcyclopentanone, 3-methylcyclopentanone,2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopentanone,cyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone,4-ethylcyclohexanone, 2,2-dimethylcyclohexanone,2,6-dimethylcyclohexanone, 2,2,6-trimethylcyclohexanone, cycloheptanone,2-methylcycloheptanone, 3-methylcycloheptanone, pylene carbonate,vinylene carbonate, ethylene carbonate, and butylene carbonate,acetate-2-methoxyethyl, acetate-2-ethoxyethyl,acetate-2-(2-ethoxyethoxy)ethyl, acetate-3-methoxy-3-methylbutyl,acetate-1-methoxy-2-propyl, dipropylene glycol, monomethylether,monoethylether, monopropylether, monobutylether, monopheylether,dipropylene glycol monoacetate, dioxane, methyl lactate, ethyl lactate,methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethylpyruvate, propyl pyruvate, methyl methoxypropionate, ethylethoxypropionate, n-methylpyrrolidone (NMP), 2-methoxyethyl ether(diglyme), ethylene glycol monom-ethyl ether, propylene glycolmonomethyl ether; ethyl lactate or methyl lactate, methyl propionate,ethyl propionate and ethyl ethoxy propionate, methylethyl ketone,cyclohexanone, 2-heptanone, carbon dioxide, cyclopentatone,cyclohexanone, ethyl 3-ethoxypropionate, ethyl lactate, propylene glycolmethyl ether acetate (PGMEA), methylene cellosolve, butyle acetate, and2-ethoxyethanol, N-methylformamide, N,N-dimethylformamide,N-methylformanilide, N-methylacetamide, N,N-dimethylacetamide,N-methylpyrrolidone, dimethylsulfoxide, benzyl ethyl ether, dihexylether, acetonylacetone, isophorone, caproic acid, caprylic acid,1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate,diethyl oxalate, diethyl maleate, γ-butyrolactone, ethylene carbonate,propylene carbonate, phenyl cellosolve acetate, or the like.

However, as one of ordinary skill in the art will recognize, thematerials listed and described above as examples of materials that maybe utilized for the photoresist solvent component of the photoresist 517are merely illustrative and are not intended to limit the embodiments.Rather, any suitable material that may dissolve the photoresist polymerresin and the PACs may be utilized to help mix and apply the photoresist517. All such materials are fully intended to be included within thescope of the embodiments.

Additionally, while individual ones of the above described materials maybe used as the photoresist solvent for the photoresist 517, inembodiments more than one of the above described materials may beutilized. For example, the photoresist solvent may comprise acombination mixture of two or more of the materials described. All suchcombinations are fully intended to be included within the scope of theembodiments.

Optionally, a photoresist cross-linking agent may also be added to thephotoresist 517. The photoresist cross-linking agent reacts with thephotoresist polymer resin within the photoresist 517 after exposure,assisting in increasing the cross-linking density of the photoresist,which helps to improve the resist pattern and resistance to dry etching.In an embodiment the photoresist cross-linking agent may be an melaminebased agent, a urea based agent, ethylene urea based agent, propyleneurea based agent, glycoluril based agent, an aliphatic cyclichydrocarbon having a hydroxyl group, a hydroxyalkyl group, or acombination of these, oxygen containing derivatives of the aliphaticcyclic hydrocarbon, glycoluril compounds, etherified amino resins,combinations of these, or the like.

Specific examples of materials that may be utilized as a photoresistcross-linking agent include melamine, acetoguanamine, benzoguanamine,urea, ethylene urea, or glycoluril with formaldehyde, glycoluril with acombination of formaldehyde and a lower alcohol,hexamethoxymethylmelamine, bismethoxymethylurea,bismethoxymethylbismethoxyethylene urea, tetramethoxymethylglycoluril,and tetrabutoxymethylglycoluril, mono-, di-, tri-, ortetra-hydroxymethylated glycoluril, mono-, di-, tri-, and/ortetra-methoxymethylated glycoluril, mono-, di-, tri-, and/ortetra-ethoxymethylated glycoluril, mono-, di-, tri-, and/ortetra-propoxymethylated glycoluril, and mono-, di-, tri-, and/ortetra-butoxymethylated glycoluril,2,3-dihydroxy-5-hydroxymethylnorbornane,2-hydroxy-5,6-bis(hydroxymethyl)norbornane, cyclohexanedimethanol,3,4,8(or 9)-trihydroxytricyclodecane, 2-methyl-2-adamantanol,1,4-dioxane-2,3-diol and 1,3,5-trihydroxycyclohexane, tetramethoxymethylglycoluril, methylpropyltetramethoxymethyl glycoluril, andmethylphenyltetramethoxymethylglycoluril,2,6-bis(hydroxymethyl)p-cresol, N-methoxymethyl- orN-butoxymethyl-melamine. Additionally, compounds obtained by reactingformaldehyde, or formaldehyde and lower alcohols with aminogroup-containing compounds, such as melamine, acetoguanamine,benzoguanamine, urea, ethylene urea and glycoluril, and substituting thehydrogen atoms of the amino group with hydroxymethyl group or loweralkoxymethyl group, examples being hexamethoxymethylmelamine,bismethoxymethyl urea, bismethoxymethylbismethoxyethylene urea,tetramethoxymethyl glycoluril and tetrabutoxymethyl glycoluril,copolymers of 3-chloro-2-hydroxypropyl methacrylate and methacrylicacid, copolymers of 3-chloro-2-hydroxypropyl methacrylate and cyclohexylmethacrylate and methacrylic acid, copolymers of3-chloro-2-hydroxypropyl methacrylate and benzyl methacrylate andmethacrylic acid, bisphenol A-di(3-chloro-2-hydroxypropyl)ether,poly(3-chloro-2-hydroxypro-pyl)ether of a phenol novolak resin,pentaerythritol tetra(3-chloro-2-hydroxypropyl)ether, trimethylolmethanetri(3-chloro-2-hydroxypropyl)ether phenol, bisphenolA-di(3-acetoxy-2-hydroxypropyl)ether,poly(3-acetoxy-2-hydroxypropyl)ethe-r of a phenol novolak resin,pentaerythritol tetra(3-acetoxy-2-hydroxyprop-yl)ether, pentaerythritolpoly(3-chloroacetoxy-2-hydroxypropyl)ether, trimethylolmethanetri(3-acetoxy-2-hydroxypropyl)ether, combinations of these, or the like.

In addition to the photoresist polymer resins, the PACs, the radicalinhibitors, the photoresist solvents, and the photoresist cross-linkingagents, the photoresist 517 may also include a number of other additivesthat will assist the photoresist 517 obtain the highest resolution. Forexample, the photoresist 517 may also include surfactants, quenchers,stabilizers, plasticizers, coloring agents, adhesion additives, surfaceleveling agents, combinations of these, or the like. Any suitableadditives may be utilized.

In an embodiment the photoresist polymer resin, the PACs, the radicalinhibitors, along with any desired additives or other agents, are addedto the photoresist solvent for application. Once added, the mixture isthen mixed in order to achieve an even composition throughout thephotoresist 517 in order to ensure that there are no defects caused byan uneven mixing or non-constant composition of the photoresist 517.Once mixed together, the photoresist 517 may either be stored prior toits usage or else used immediately.

Once ready, the photoresist 517 may be utilized by initially applyingthe photoresist 517 onto the second seed layer 515. The photoresist 517may be applied to the second seed layer 515 so that the photoresist 517coats an upper exposed surface of the second seed layer 515, and may beapplied using a process such as a spin-on coating process, a dip coatingmethod, an air-knife coating method, a curtain coating method, awire-bar coating method, a gravure coating method, a lamination method,an extrusion coating method, combinations of these, or the like. In anembodiment the photoresist 517 may be applied such that it has athickness over the surface of the second seed layer 515 of between about10 nm and about 300 nm, such as about 150 nm.

Once the photoresist 517 has been applied to the semiconductorsubstrate, a pre-bake of the photoresist 517 is performed in order tocure and dry the photoresist 517 prior to exposure to finish theapplication of the photoresist 517. The curing and drying of thephotoresist 517 removes the photoresist solvent component while leavingbehind the photoresist polymer resin, the PACs, the radical inhibitors,the photoresist cross-linking agents, and the other chosen additives. Inan embodiment the pre-bake may be performed at a temperature suitable toevaporate the photoresist solvent, such as between about 40° C. and 150°C., although the precise temperature depends upon the materials chosenfor the photoresist 517. The pre-bake is performed for a time sufficientto cure and dry the photoresist 517, such as between about 10 seconds toabout 5 minutes, such as about 90 seconds.

FIG. 6A illustrates an exposure of the photoresist 517 to form anexposed region 601 and an unexposed region 603 within the photoresist517. In an embodiment the exposure may be initiated by placing thesemiconductor device 100 and the photoresist 517, once cured and dried,into an imaging device 600 for exposure. The imaging device 600 maycomprise a support plate 605, an energy source 607, a patterned mask 609between the support plate 605 and the energy source 607, and optics 617.In an embodiment the support plate 605 is a surface to which thesemiconductor device 100 and the photoresist 517 may be placed orattached to and which provides support and control to the carriersubstrate 101 during exposure of the photoresist 517. Additionally, thesupport plate 605 may be movable along one or more axes, as well asproviding any desired heating or cooling to the carrier substrate 101and photoresist 517 in order to prevent temperature gradients fromaffecting the exposure process.

In an embodiment the energy source 607 supplies energy 611 such as lightto the photoresist 517 in order to induce a reaction of the PACs, whichin turn reacts with the polymer resin to chemically alter those portionsof the photoresist 517 to which the energy 611 impinges. In anembodiment the energy 611 may be electromagnetic radiation, such asg-rays (with a wavelength of about 436 nm), i-rays (with a wavelength ofabout 365 nm), ultraviolet radiation, far ultraviolet radiation, extremeultraviolet radiation, x-rays, electron beams, or the like. The energysource 607 may be a source of the electromagnetic radiation, and may bea KrF excimer laser light (with a wavelength of 248 nm), an ArF excimerlaser light (with a wavelength of 193 nm), a F2 excimer laser light(with a wavelength of 157 nm), or the like, although any other suitablesource of energy 611, such as mercury vapor lamps, xenon lamps, carbonarc lamps or the like, may also be utilized.

The patterned mask 609 is located between the energy source 607 and thephotoresist 517 in order to block portions of the energy 611 to form apatterned energy 615 prior to the energy 611 actually impinging upon thephotoresist 517. In an embodiment the patterned mask 609 may comprise aseries of layers (e.g., substrate, absorbance layers, anti-reflectivecoating layers, shielding layers, etc.) to reflect, absorb, or otherwiseblock portions of the energy 611 from reaching those portions of thephotoresist 517 which are not desired to be illuminated. The desiredpattern may be formed in the patterned mask 609 by forming openingsthrough the patterned mask 609 in the desired shape of illumination.

Optics (represented in FIG. 6A by the trapezoid labeled 617) may be usedto concentrate, expand, reflect, or otherwise control the energy 611 asit leaves the energy source 607, is patterned by the patterned mask 609,and is directed towards the photoresist 517. In an embodiment the optics617 comprise one or more lenses, mirrors, filters, combinations ofthese, or the like to control the energy 611 along its path.Additionally, while the optics 617 are illustrated in FIG. 6A as beingbetween the patterned mask 609 and the photoresist 517, elements of theoptics 617 (e.g., individual lenses, mirrors, etc.) may also be locatedat any location between the energy source 607 (where the energy 611 isgenerated) and the photoresist 517.

In an embodiment the semiconductor device 100 with the photoresist 517is placed on the support plate 605. Once the pattern has been aligned tothe semiconductor device 100, the energy source 607 generates thedesired energy 611 (e.g., light) which passes through the patterned mask609 and the optics 617 on its way to the photoresist 517. The patternedenergy 615 impinging upon portions of the photoresist 517 induces areaction of the PACs within the photoresist 517. The chemical reactionproducts of the PACs' absorption of the patterned energy 615 (e.g.,acids/bases/free radicals) then reacts with the polymer resin,chemically altering the photoresist 517 in those portions that wereilluminated through the patterned mask 609.

FIG. 6B illustrates a close up view of the box labeled 621 in FIG. 6Aduring the exposure process. As can be seen, during the exposureprocess, the desired energy 611 (e.g., light) does not come straightdown but is, rather, made up of a plurality of individual beams whichfirst converge and then diverge around a center point C_(P). When theindividual beams converge close enough to each other, and before theindividual beams diverge far enough from each other, the individualbeams will be focused with respect to each other and with respect to thephotoresist 517. In an embodiment the energy 611 is focused so that allof the various divergent beams of the energy 611 are converged and areconcentrated into an in-focus area 613 with a desired width. In aparticular embodiment the in-focus area 613 will have a first width W₁of between about 5 μm and about 500 μm, such as about 40 μm. However,any suitable width may be utilized.

Additionally, in embodiment in which the in-focus area 613 has the firstwidth W₁, the in-focus area 613 will also have a first height H₁ that iscentered around the center point C_(P) of the in-focus area 613. Thefirst height H₁ may be between about 1 μm and about 100 μm, such asabout 40 μm. However, any suitable dimensions may be utilized.

However, in order to help the subsequently formed third externalconnection 901 avoid cracking and reduce the stress, the exposureprocess of the photoresist 517 is tuned in order to help shape the finalstructure of the third external connection 901. For example, in oneembodiment the placement of the center point C_(P) of the in-focus area613 is not placed to be within the photoresist 517 itself. Rather, thecenter point C_(P) of the in-focus area 613 is placed a first distanceD₁ below the uppermost surface of the second seed layer 515. Forexample, in one embodiment the center point C_(P) of the in-focus area613 may be placed such that the first distance D₁ is between about 60 μmand about 70 μm, such as about 65 μm, below the uppermost surface of thesecond seed layer 515.

FIG. 6C illustrates another embodiment in which the in-focus area 613 isshifted away from being located in the center of the photoresist 517. Inthis embodiment, however, instead of being the center point C_(P) beingshifted downward such that the center point C_(P) is located below thebottom surface of the photoresist 517, the center point C_(P) is shiftedin an opposite direction such that the center point C_(P) is locatedover the photoresist 517. In this embodiment the center point C_(P) maybe shifted a second distance D₂ of between about 0 μm and about 60 μm,such as about 10 μm. However, any suitable dimension may be utilized.

FIG. 6D illustrates one resulting structure of the photoresist 517 afterthe exposure of the photoresist 517 with the center point C_(P) of thein-focus area 613 being shifted to be below the photoresist 517. As canbe seen, with the center point C_(P) shifted, the bottom portion of theunexposed region 603 is not straight but is, rather, angled with theremaining portions of the sidewalls of the unexposed region 603.Additionally, the unexposed region 603 is angled with respect to thesecond seed layer 515. This angled shape helps with the formation of thethird external connection 901 (not illustrated in FIG. 6D butillustrated and described further below with respect to FIG. 9).

After the photoresist 517 has been exposed, a post-exposure baking maybe used in order to assist in the generating, dispersing, and reactingof the acid/base/free radical generated from the impingement of thepatterned energy 615 upon the PACs during the exposure. Such assistancehelps to create or enhance chemical reactions which generate chemicaldifferences between the exposed region 601 and the unexposed region 603within the photoresist 517. These chemical differences also causeddifferences in the solubility between the exposed region 601 and theunexposed region 603. In an embodiment this post-exposure baking mayoccur at temperatures of between about 40° C. and about 200° C. for aperiod of between about 10 seconds and about 10 minutes. However, anysuitable temperatures and times may be utilized.

FIGS. 7A-7B illustrate a development of the photoresist 517 with the useof a developer 701 after the exposure of the photoresist 517 (with FIG.7B illustrating a close up view of the dashed box labeled 621 in FIG.7A). After the photoresist 517 has been exposed and the post-exposurebaking has occurred, the photoresist 517 may be developed using either anegative tone developer or a positive tone developer, depending upon thedesired pattern for the photoresist 517. In an embodiment in which theunexposed region 603 of the photoresist 517 is desired to be removed toform a negative tone, a negative tone developer such as an organicsolvent or critical fluid may be utilized to remove those portions ofthe photoresist 517 which were not exposed to the patterned energy 615and, as such, retain their original solubility. Specific examples ofmaterials that may be utilized include hydrocarbon solvents, alcoholsolvents, ether solvents, ester solvents, critical fluids, combinationsof these, or the like. Specific examples of materials that can be usedfor the negative tone solvent include hexane, heptane, 2-heptanone,n-butyl acetate, octane, toluene, xylene, dichloromethane, chloroform,carbon tetrachloride, trichloroethylene, methanol, ethanol, propanol,butanol, critical carbon dioxide, diethyl ether, dipropyl ether, dibutylether, ethyl vinyl ether, dioxane, propylene oxide, tetrahydrofuran,cellosolve, methyl cellosolve, butyl cellosolve, methyl carbitol,diethylene glycol monoethyl ether, acetone, methyl ethyl ketone, methylisobutyl ketone, isophorone, cyclohexanone, methyl acetate, ethylacetate, propyl acetate, butyl acetate, pyridine, formamide,N,N-dimethyl formamide, or the like.

If a positive tone development is desired, a positive tone developersuch as a basic aqueous solution may be utilized to remove thoseportions of the photoresist 517 which were exposed to the patternedenergy 615 and which have had their solubility modified and changedthrough the chemical reactions. Such basic aqueous solutions may includetetra methyl ammonium hydroxide (TMAH), tetra butyl ammonium hydroxide,sodium hydroxide, potassium hydroxide, sodium carbonate, sodiumbicarbonate, sodium silicate, sodium metasilicate, aqueous ammonia,monomethylamine, dimethylamine, trimethylamine, monoethylamine,diethylamine, triethylamine, monoisopropylamine, diisopropylamine,triisopropylamine, monobutylamine, dibutylamine, monoethanolamine,diethanolamine, triethanolamine, dimethylaminoethanol,diethylaminoethanol, ammonia, caustic soda, caustic potash, sodiummetasilicate, potassium metasilicate, sodium carbonate,tetraethylammonium hydroxide, combinations of these, or the like.

However, as one of ordinary skill in the art will recognize, the abovedescription of positive tone developers and negative tone developers areonly intended to be illustrative and are not intended to limit theembodiments to only the developers listed above. Rather, any suitabletype of developer, including acid developers or even water developers,that may be utilized to selectively remove a portion of the photoresist517 that has a different property (e.g., solubility) than anotherportion of the photoresist 517, may be utilized, and all such developersare fully intended to be included within the scope of the embodiments.

FIG. 7A illustrates an application of the developer 701 to thephotoresist 517 using, e.g., a spin-on process. In this process thedeveloper 701 is applied to the photoresist 517 from above thephotoresist 517 while the semiconductor device 100 (and the photoresist517) is rotated. In an embodiment the developer 701 may be supplied at aflow rate of between about 10 ml/min and about 2000 ml/min, such asabout 1000 ml/min, while the semiconductor device 100 is being rotatedat a speed of between about 100 rpm and about 3500 rpm, such as about1500 rpm. In an embodiment the developer 701 may be at a temperature ofbetween about 10° C. and about 80° C., such as about 50° C., and thedevelopment may continue for between about 1 minute to about 60 minutes,such as about 30 minutes.

However, while the spin-on method described herein is one suitablemethod for developing the photoresist 517 after exposure, it is intendedto be illustrative and is not intended to limit the embodiments. Rather,any suitable method for development, including dip processes, puddleprocesses, spray-on processes, combinations of these, or the like, maybe used. All such development processes are fully intended to beincluded within the scope of the embodiments.

FIG. 7B illustrates a cross-section of the development process in whicha negative tone developer is utilized. As illustrated, the developer 701is applied to the photoresist 517 and dissolves the unexposed region 603of the photoresist 517. This dissolving and removing of the unexposedregion 603 of the photoresist 517 leaves behind an opening within thephotoresist 517 that patterns the photoresist 517 in the shape of thepatterned energy 615, thereby transferring the pattern of the patternedmask 609 to the photoresist 517.

FIG. 7B also illustrates that, after the development process has beencompleted and the developer 701 has been removed from the photoresist517, the opening within the photoresist 517 will have a bottom portionthat is angled to intercept the second seed layer 515. In an embodimentthe bottom portion may be at a first angle α₁ of between about 5° andabout 85°, such as about 45°. However, any suitable angle may beutilized.

Additionally, the bottom portion may be formed to have a second width W₂of between about 0.1 μm and about 10 μm, such as about 5 μm. The bottomportion may also have a second height H₂ of between about 0.1 μm andabout 10 μm, such as about 5 μm. However, any suitable dimensions may beutilized.

FIG. 8 illustrates a close up view of the dashed box labeled 621 in FIG.7A during a post developed annealing process (represented in FIG. 8 bythe wavy lines labeled 801) that is utilized to help reshape the openingthrough the photoresist 517. In an embodiment the annealing process 801may be a thermal anneal wherein the photoresist 517 is heated within,e.g., a furnace, within an inert atmosphere. The annealing process 801may be performed at a temperature that is above the glass transitiontemperature (T_(g)), such as between about 100° C. and about 130° C.,such as about 120° C., and may be continued for a time of between about120 s and about 7 min, such as about 5 min. However, any suitableprocess conditions may be utilized.

During the annealing process 801, the temperature will be raised abovethe glass transition temperature of the photoresist 517, and thephotoresist 517 will slightly melt and partially reshape itself, therebyalso reshaping the openings through the photoresist 517. As such, whilethe angled bottom portion will still be present after the annealingprocess 801, the annealing process 801 will at least partially reshapethe bottom portion such that after the annealing process 801 the bottomportion may be at a second angle α₂ or flare angle that is differentfrom the first angle α₁, such as being between about 10° and about 85°,such as about 45°. Further, after the annealing process 801 the bottomportion may be formed to have a third width W₃ of between about 0.5 μmand about 11 μm, such as about 5 μm, and a third height H₃ of betweenabout 0.5 μm and about 11 μm, such as about 5 μm. However, any suitabledimensions may be utilized.

FIG. 9 illustrates a close-up view of the dashed box labeled 621 in FIG.7A in which, once the photoresist 517 has been patterned and theannealing process 801 has been performed, the third external connection901 may be formed within the openings of the photoresist 517. In anembodiment the third external connection 901 may be, for example, acopper pillar and may comprise one or more conductive materials, such ascopper, tungsten, other conductive metals, or the like, and may beformed, for example, by electroplating, electroless plating, or thelike. In an embodiment, an electroplating process is used wherein thesecond seed layer 515 and the photoresist 517 are submerged or immersedin an electroplating solution such as a copper sulfate (CuSO₄)containing solution. The second seed layer 515 surface is electricallyconnected to the negative side of an external DC power supply such thatthe second seed layer 515 functions as the cathode in the electroplatingprocess. A solid conductive anode, such as a copper anode, is alsoimmersed in the solution and is attached to the positive side of thepower supply. The atoms from the anode are dissolved into the solution,from which the cathode, e.g., the second seed layer 515, acquires thedissolved atoms, thereby plating the exposed conductive areas of thesecond seed layer 515 within the opening of the photoresist 517.

However, by using the exposure process and reshaping processes describedherein, at least some of the negative side effects of the platingprocess may be reduced or eliminated. In particular, by reshaping theopening through the photoresist 517, the profile can help to avoid theplating solution (e.g., the CuSO₄ plating solution) from penetratinginto the photoresist and causing a risk of underplating during theplating process.

Once the third external connection 901 has been formed using thephotoresist 517 and the second seed layer 515, the photoresist 517 maybe removed using a suitable removal process. In an embodiment, a plasmaashing process may be used to remove the photoresist 517, whereby thetemperature of the photoresist 517 may be increased until thephotoresist 517 experiences a thermal decomposition and may be removed.However, any other suitable process, such as a wet strip, may beutilized. The removal of the photoresist 517 may expose the underlyingportions of the second seed layer 515.

By plating the third external connection 901 into an opening formedthrough the photoresist 517, the third external connection 901 will takeon the shape of the opening through the photoresist 517. As such, thethird external connection 901 will also have a middle portion outside ofthe sixth passivation layer 513 and the second seed layer 515, whereinthe middle portion is angled inwards at an angle to the underlying seedlayer. In an embodiment the middle portion has the second angle α₂, thethird width W₃, and the third height H₃. However, any suitabledimensions may be utilized.

FIG. 10 illustrates that, once the second seed layer 515 has beenexposed, a removal of the exposed portions of the second seed layer 515may be performed. In an embodiment the exposed portions of the secondseed layer 515 (e.g., those portions that are not covered by the thirdexternal connection 901) may be removed by, for example, a wet or dryetching process. For example, in a dry etching process reactants may bedirected towards the second seed layer 515 using the third externalconnection 901 as masks, thereby forming the second seed layer 515 tohave a straight sidewall perpendicular with a surface of the sixthpassivation layer 513. In another embodiment, etchants may be sprayed orotherwise put into contact with the second seed layer 515 in order toremove the exposed portions of the second seed layer 515.

By forming the third external connection 901 as described above, theprofile of the third external connection 901 can be modified tounder-cut the third external connection 901 and help to reduce oreliminate cracks that can form between the third external connection 901and the underlying passivation layer. In particular, the under-cut ofthe third external connection 901 helps to reduce compressional stressduring reliability torture tests. With the possibility of cracksreduced, a smaller pitch size can be obtained while still passingtorture tests.

FIG. 11 illustrates a formation of fourth external connections 1101 onthe third external connections 901. In an embodiment the fourth externalconnections 1101 may be contact bumps such as microbumps or controlledcollapse chip connection (C4) bumps and may comprise a material such astin, or other suitable materials, such as silver or copper. In anembodiment in which the fourth external connections 1101 are contactbumps, the fourth external connections 1101 may comprise a material suchas tin, or other suitable materials, such as silver, lead-free tin, orcopper. In an embodiment in which the fourth external connection 1101 isa tin solder bump, the fourth external connection 1101 may be formed byinitially forming a layer of tin through such commonly used methods suchas evaporation, electroplating, printing, solder transfer, ballplacement, etc, to a thickness of, e.g., about 100 μm. Once a layer oftin has been formed on the structure, a reflow may be performed in orderto shape the material into the desired bump shape which may have acritical dimension of between about 60 μm and about 100 μm, and may beformed in either a round shape or an elliptical shape.

Additionally, in an embodiment the fourth external connections 1101 maybe formed in the shape of a circle in a top down view. However, this ismerely intended to be illustrative and is not intended to be limit theembodiments. Rather, any suitable shape, such as an elliptical shape, ora combination of shapes, may also be utilized.

FIG. 12 illustrates a debonding of the carrier substrate 101 from thefirst semiconductor device 201 and the second semiconductor device 301.In an embodiment the fourth external connection 1101 and, hence, thestructure including the first semiconductor device 201 and the secondsemiconductor device 301, may be attached to a ring structure 1201. Thering structure 1201 may be a metal ring intended to provide support andstability for the structure during and after the debonding process. Inan embodiment the fourth external connection 1101, the firstsemiconductor device 201, and the second semiconductor device 301 areattached to the ring structure using, e.g., a ultraviolet tape 1203,although any other suitable adhesive or attachment may be used.

Once the fourth external connection 1101 and, hence, the structureincluding the first semiconductor device 201 and the secondsemiconductor device 301 are attached to the ring structure 1201, thecarrier substrate 101 may be debonded from the structure including thefirst semiconductor device 201 and the second semiconductor device 301using, e.g., a thermal process to alter the adhesive properties of theadhesive layer 103. In a particular embodiment an energy source such asan ultraviolet (UV) laser, a carbon dioxide (CO₂) laser, or an infrared(IR) laser, is utilized to irradiate and heat the adhesive layer 103until the adhesive layer 103 loses at least some of its adhesiveproperties. Once performed, the carrier substrate 101 and the adhesivelayer 103 may be physically separated and removed from the structurecomprising the fourth external connection 1101, the first semiconductordevice 201, and the second semiconductor device 301.

FIG. 12 additionally illustrates a patterning of the polymer layer 105in order to expose the vias 111 (along with the associated first seedlayer 107). In an embodiment the polymer layer 105 may be patternedusing, e.g., a laser drilling method. In such a method a protectivelayer, such as a light-to-heat conversion (LTHC) layer or a hogomaxlayer (not separately illustrated in FIG. 12) is first deposited overthe polymer layer 105. Once protected, a laser is directed towards thoseportions of the polymer layer 105 which are desired to be removed inorder to expose the underlying vias 111. During the laser drillingprocess the drill energy may be in a range from 0.1 mJ to about 30 mJ,and a drill angle of about 0 degree (perpendicular to the polymer layer105) to about 85 degrees to normal of the polymer layer 105. In anembodiment the patterning may be performed to form fourth openings 1205over the vias 111 to have a width of between about 100 μm and about 300μm, such as about 200 μm.

In another embodiment, the polymer layer 105 may be patterned byinitially applying a photoresist (not individually illustrated in FIG.12) to the polymer layer 105 and then exposing the photoresist to apatterned energy source (e.g., a patterned light source) so as to inducea chemical reaction, thereby inducing a physical change in thoseportions of the photoresist exposed to the patterned light source. Adeveloper is then applied to the exposed photoresist to take advantageof the physical changes and selectively remove either the exposedportion of the photoresist or the unexposed portion of the photoresist,depending upon the desired pattern, and the underlying exposed portionof the polymer layer 105 are removed with, e.g., a dry etch process.However, any other suitable method for patterning the polymer layer 105may be utilized.

FIG. 13 illustrates a placement of a backside ball pad 1301 within theopenings of the polymer layer 105 in order to protect the now exposedvias 111. In an embodiment the backside ball pads 1301 may comprise aconductive material such as solder on paste or an oxygen solderprotection (OSP), although any suitable material may be utilized. In anembodiment the backside ball pads 1301 may be applied using a stencil,although any suitable method of application may be utilized, and thenreflowed in order to form a bump shape.

FIG. 13 also illustrates a placement and patterning of a backsideprotection layer 1303 over the backside ball pads 1301, effectivelysealing the joint between the backside ball pads 1301 and the vias 111from intrusion by moisture. In an embodiment the backside protectionlayer 1303 may be a protective material such as a PBO, Solder Resistance(SR), Lamination Compound (LC) tape, Ajinomoto build-up film (ABF),non-conductive paste (NCP), non-conductive film (NCF), patternedunderfill (PUF), warpage improvement adhesive (WIA), liquid moldingcompound V9, combinations of these, or the like. However, any suitablematerial may also be used. The backside protection layer 1303 may beapplied using a process such as screen printing, lamination, spincoating, or the like, to a thickness of between about 1 μm to about 200μm.

FIG. 13 also illustrates that, once the backside protection layer 1303has been placed, the backside protection layer 1303 may be patterned inorder to expose the backside ball pads 1301. In an embodiment thebackside protection layer 1303 may be patterned using, e.g., a laserdrilling method, by which a laser is directed towards those portions ofthe backside protection layer 1303 which are desired to be removed inorder to expose the backside ball pads 1301. During the laser drillingprocess the drill energy may be in a range from 0.1 mJ to about 30 mJ,and a drill angle of about 0 degree (perpendicular to the backsideprotection layer 1303) to about 85 degrees to normal of the backsideprotection layer 1303. In an embodiment the exposure may form openingswith a diameter of between about 30 μm and about 300 μm, such as about150 μm.

In another embodiment, the backside protection layer 1303 may bepatterned by initially applying a photoresist (not individuallyillustrated in FIG. 13) to the backside protection layer 1303 and thenexposing the photoresist to a patterned energy source (e.g., a patternedlight source) so as to induce a chemical reaction, thereby inducing aphysical change in those portions of the photoresist exposed to thepatterned light source. A developer is then applied to the exposedphotoresist to take advantage of the physical changes and selectivelyremove either the exposed portion of the photoresist or the unexposedportion of the photoresist, depending upon the desired pattern, and theunderlying exposed portion of the backside protection layer 1303 areremoved with, e.g., a dry etch process. However, any other suitablemethod for patterning the backside protection layer 1303 may beutilized.

FIG. 13 also illustrates a bonding of the backside ball pads 1301 to afirst package 1300. In an embodiment the first package 1300 may comprisea third substrate 1305, a third semiconductor device 1307, a fourthsemiconductor device 1309 (bonded to the third semiconductor device1307), third contact pads 1311, a second encapsulant 1313, and fifthexternal connections 1315. In an embodiment the third substrate 1305 maybe, e.g., a packaging substrate comprising internal interconnects (e.g.,through substrate vias 1317) to connect the third semiconductor device1307 and the fourth semiconductor device 1309 to the backside ball pads1301.

In another embodiment, the third substrate 1305 may be an interposerused as an intermediate substrate to connect the third semiconductordevice 1307 and the fourth semiconductor device 1309 to the backsideball pads 1301. In this embodiment the third substrate 1305 may be,e.g., a silicon substrate, doped or undoped, or an active layer of asilicon-on-insulator (SOI) substrate. However, the third substrate 1305may also be a glass substrate, a ceramic substrate, a polymer substrate,or any other substrate that may provide a suitable protection and/orinterconnection functionality. These and any other suitable materialsmay be used for the third substrate 1305.

The third semiconductor device 1307 may be a semiconductor devicedesigned for an intended purpose such as being a logic die, a centralprocessing unit (CPU) die, a memory die (e.g., a DRAM die), combinationsof these, or the like. In an embodiment the third semiconductor device1307 comprises integrated circuit devices, such as transistors,capacitors, inductors, resistors, metallization layers (not shown), andthe like, therein, as desired for a particular functionality. In anembodiment the third semiconductor device 1307 is designed andmanufactured to work in conjunction with or concurrently with the firstsemiconductor device 201.

The fourth semiconductor device 1309 may be similar to the thirdsemiconductor device 1307. For example, the fourth semiconductor device1309 may be a semiconductor device designed for an intended purpose(e.g., a DRAM die) and comprising integrated circuit devices for adesired functionality. In an embodiment the fourth semiconductor device1309 is designed to work in conjunction with or concurrently with thefirst semiconductor device 201 and/or the third semiconductor device1307.

The fourth semiconductor device 1309 may be bonded to the thirdsemiconductor device 1307. In an embodiment the fourth semiconductordevice 1309 is only physically bonded with the third semiconductordevice 1307, such as by using an adhesive. In this embodiment the fourthsemiconductor device 1309 and the third semiconductor device 1307 may beelectrically connected to the third substrate 1305 using, e.g., wirebonds 1319, although any suitable electrical bonding may be utilized.

In another embodiment, the fourth semiconductor device 1309 may bebonded to the third semiconductor device 1307 both physically andelectrically. In this embodiment the fourth semiconductor device 1309may comprise external connections (not separately illustrated in FIG.13) that connect with external connections (also not separatelyillustrated in FIG. 13) on the third semiconductor device 1307 in orderto interconnect the fourth semiconductor device 1309 with the thirdsemiconductor device 1307.

The third contact pads 1311 may be formed on the third substrate 1305 toform electrical connections between the third semiconductor device 1307and, e.g., the fifth external connections 1315. In an embodiment thethird contact pads 1311 may be formed over and in electrical contactwith electrical routing (such as through substrate vias 1317) within thethird substrate 1305. The third contact pads 1311 may comprise aluminum,but other materials, such as copper, may be used. The third contact pads1311 may be formed using a deposition process, such as sputtering, toform a layer of material (not shown) and portions of the layer ofmaterial may then be removed through a suitable process (such asphotolithographic masking and etching) to form the third contact pads1311. However, any other suitable process may be utilized to form thethird contact pads 1311. The third contact pads 1311 may be formed tohave a thickness of between about 0.5 μm and about 4 μm, such as about1.45 μm.

The second encapsulant 1313 may be used to encapsulate and protect thethird semiconductor device 1307, the fourth semiconductor device 1309,and the third substrate 1305. In an embodiment the second encapsulant1313 may be a molding compound and may be placed using a molding device(not illustrated in FIG. 13). For example, the third substrate 1305, thethird semiconductor device 1307, and the fourth semiconductor device1309 may be placed within a cavity of the molding device, and the cavitymay be hermetically sealed. The second encapsulant 1313 may be placedwithin the cavity either before the cavity is hermetically sealed orelse may be injected into the cavity through an injection port. In anembodiment the second encapsulant 1313 may be a molding compound resinsuch as polyimide, PPS, PEEK, PES, a heat resistant crystal resin,combinations of these, or the like.

Once the second encapsulant 1313 has been placed into the cavity suchthat the second encapsulant 1313 encapsulates the region around thethird substrate 1305, the third semiconductor device 1307, and thefourth semiconductor device 1309, the second encapsulant 1313 may becured in order to harden the second encapsulant 1313 for optimumprotection. While the exact curing process is dependent at least in parton the particular material chosen for the second encapsulant 1313, in anembodiment in which molding compound is chosen as the second encapsulant1313, the curing could occur through a process such as heating thesecond encapsulant 1313 to between about 100° C. and about 130° C., suchas about 125° C. for about 60 sec to about 3000 sec, such as about 600sec. Additionally, initiators and/or catalysts may be included withinthe second encapsulant 1313 to better control the curing process.

However, as one having ordinary skill in the art will recognize, thecuring process described above is merely an exemplary process and is notmeant to limit the current embodiments. Other curing processes, such asirradiation or even allowing the second encapsulant 1313 to harden atambient temperature, may be used. Any suitable curing process may beused, and all such processes are fully intended to be included withinthe scope of the embodiments discussed herein.

In an embodiment the fifth external connections 1315 may be formed toprovide an external connection between the third substrate 1305 and,e.g., the backside ball pads 1301. The fifth external connections 1315may be contact bumps such as microbumps or controlled collapse chipconnection (C4) bumps and may comprise a material such as tin, or othersuitable materials, such as silver or copper. In an embodiment in whichthe fifth external connections 1315 are tin solder bumps, the fifthexternal connections 1315 may be formed by initially forming a layer oftin through any suitable method such as evaporation, electroplating,printing, solder transfer, ball placement, etc, to a thickness of, e.g.,about 100 μm. Once a layer of tin has been formed on the structure, areflow is performed in order to shape the material into the desired bumpshape.

Once the fifth external connections 1315 have been formed, the fifthexternal connections 1315 are aligned with and placed into physicalcontact with the backside ball pads 1301, and a bonding is performed.For example, in an embodiment in which the fifth external connections1315 are solder bumps, the bonding process may comprise a reflow processwhereby the temperature of the fifth external connections 1315 is raisedto a point where the fifth external connections 1315 will liquefy andflow, thereby bonding the first package 1300 to the backside ball pads1301 once the fifth external connections 1315 resolidifies.

FIG. 13 additionally illustrates the bonding of a second package 1321 tothe backside ball pads 1301. In an embodiment the second package 1321may be similar to the first package 1300, and may be bonded to thebackside ball pads 1301 utilizing similar processes. However, the secondpackage 1321 may also be different from the first package 1300.

FIG. 14 illustrates a debonding of the fourth external connections 1101from the ring structure 1201 and a singulation of the structure to forma first integrated fan out package-on-package (InFO-POP) structure 1400.In an embodiment the fourth external connections 1101 may be debondedfrom the ring structure 1201 by initially bonding the first package 1300and the second package 1321 to a second ring structure using, e.g., asecond ultraviolet tape. Once bonded, the ultraviolet tape 1203 may beirradiated with ultraviolet radiation and, once the ultraviolet tape1203 has lost its adhesiveness, the fourth external connections 1101 maybe physically separated from the ring structure 1201.

Once debonded, a singulation of the structure to form the first InFO-POPstructure 1400 is performed. In an embodiment the singulation may beperformed by using a saw blade (not shown) to slice through theencapsulant 401 and the polymer layer 105 between the vias 111, therebyseparating one section from another to form the first InFO-POP structure1400 with the first semiconductor device 201. However, as one ofordinary skill in the art will recognize, utilizing a saw blade tosingulate the first InFO-POP structure 1400 is merely one illustrativeembodiment and is not intended to be limiting. Other methods forsingulating the first InFO-POP structure 1400, such as utilizing one ormore etches to separate the first InFO-POP structure 1400, may also beutilized. These methods and any other suitable methods may be utilizedto singulate the first InFO-POP structure 1400.

In accordance with an embodiment, a method of manufacturing asemiconductor device includes: applying a photoresist over a seed layer;exposing the photoresist to a patterned energy source, the patternedenergy source having an in-focus area with a center point, the centerpoint located below a surface of the photoresist facing towards the seedlayer; developing the photoresist to form an opening; and plating anexternal connector into the opening. In an embodiment the method furtherincludes annealing the photoresist after the developing the photoresist,wherein the annealing the photoresist reshapes the opening. In anembodiment the annealing the photoresist raises a temperature of thephotoresist to between about 110° C. and about 130° C. In an embodimentthe center point is located below the surface of the photoresist adistance of between about 60 μm and about 70 μm. In an embodiment themethod further includes removing a portion of the seed layer not coveredby the external connector. In an embodiment the developing thephotoresist comprises removing an unexposed portion of the photoresist.In an embodiment the seed layer is located over an encapsulant around asemiconductor device and a through encapsulant via.

In accordance with another embodiment, a method of manufacturing asemiconductor device includes: exposing a photoresist to a patternedenergy source, the photoresist being located over an encapsulant locatedbetween a semiconductor die and a through encapsulant via; developingthe photoresist to form an opening with a first shape; performing apost-development baking process to reshape the opening into a secondshape different from the first shape, wherein the second shape comprisesa flare near a bottom of the opening; and plating a conductive materialinto the opening. In an embodiment the exposing the photoresist focusesthe patterned energy source to form an in-focus area, the in-focus areahaving a center point below the photoresist. In an embodiment the centerpoint is located below the photoresist a distance of between about 60 μmand about 70 μm. In an embodiment the post-development baking processraises a temperature of the photoresist to a temperature between about100° C. and about 130° C. In an embodiment the flare extends in a firstdirection parallel with a major surface of the encapsulant a firstdistance, the first distance being between about 0.1 μm and about 10 μm.In an embodiment the flare extends in a second direction perpendicularwith the major surface of the encapsulant a second distance, the seconddistance between about 0.5 μm and about 10 μm. In an embodiment theflare is located at a flare angle of between about 10° and about 85°.

In accordance with yet another embodiment, a semiconductor deviceincludes: a semiconductor die; an encapsulant encapsulating thesemiconductor die; a through encapsulant via extending from a first sideof the encapsulant to a second side of the encapsulant; a passivationlayer over the encapsulant; and an external connector over theencapsulant, the external connector including: a first portion with afirst width, the first portion extending through the passivation layer;a second portion with a second width larger than the first width, thesecond portion being located outside of the passivation layer; and atapered portion extending from the second portion to the first portion.In an embodiment the tapered portion is located at a tapered angle to aline, the line being parallel with a major surface of the encapsulant,the tapered angle being between about 10° and about 85°. In anembodiment the semiconductor device further includes a solder ball inphysical contact with the external connector, the solder ball having anoval shape. In an embodiment the semiconductor device further includes asolder ball in physical contact with the external connector, the solderball having a round shape. In an embodiment the semiconductor devicefurther includes a seed layer located between the external connector andthe passivation layer, the seed layer having a straight sidewallperpendicular to a surface of the passivation layer. In an embodimentthe semiconductor device further includes a redistribution layer locatedbetween the external connector and the encapsulant.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A method of manufacturing a semiconductor device,the method comprising: applying a photoresist over a seed layer;exposing the photoresist to a patterned energy source, the patternedenergy source having an in-focus area with a center point, the centerpoint located below a surface of the photoresist facing towards the seedlayer; developing the photoresist to form an opening; and plating anexternal connector into the opening.
 2. The method of claim 1, furthercomprising annealing the photoresist after the developing thephotoresist, wherein the annealing the photoresist reshapes the opening.3. The method of claim 2, wherein the annealing the photoresist raises atemperature of the photoresist to between about 110° C. and about 130°C.
 4. The method of claim 1, wherein the center point is located belowthe surface of the photoresist a distance of between about 60 μm andabout 70 μm.
 5. The method of claim 1, further comprising removing aportion of the seed layer not covered by the external connector.
 6. Themethod of claim 1, wherein the developing the photoresist comprisesremoving an unexposed portion of the photoresist.
 7. The method of claim1, wherein the seed layer is located over an encapsulant around asemiconductor device and a through encapsulant via.
 8. A method ofmanufacturing a semiconductor device, the method comprising: exposing aphotoresist to a patterned energy source, the photoresist being locatedover an encapsulant located between a semiconductor die and a throughencapsulant via; developing the photoresist to form an opening with afirst shape; performing a post-development baking process to reshape theopening into a second shape different from the first shape, wherein thesecond shape comprises a flare near a bottom of the opening; and platinga conductive material into the opening.
 9. The method of claim 8,wherein the exposing the photoresist focuses the patterned energy sourceto form an in-focus area, the in-focus area having a center point belowthe photoresist.
 10. The method of claim 9, wherein the center point islocated below the photoresist a distance of between about 60 μm andabout 70 μm.
 11. The method of claim 8, wherein the post-developmentbaking process raises a temperature of the photoresist to a temperaturebetween about 100° C. and about 130° C.
 12. The method of claim 8,wherein the flare extends in a first direction parallel with a majorsurface of the encapsulant a first distance, the first distance beingbetween about 0.1 μm and about 10 μm.
 13. The method of claim 12,wherein the flare extends in a second direction perpendicular with themajor surface of the encapsulant a second distance, the second distancebetween about 0.5 μm and about 11 μm.
 14. The method of claim 8, whereinthe flare is located at a flare angle of between about 10° and about85°.
 15. A method of manufacturing a semiconductor device, the methodcomprising: placing a semiconductor die adjacent to a throughencapsulant via, the through encapsulant via also being adjacent to aseed layer; encapsulating the semiconductor die, the seed layer, and thethrough encapsulant via with an encapsulant, wherein after theencapsulating a combination of the through encapsulant via and the seedlayer extends from a first side of the encapsulant to a second side ofthe encapsulant; placing a passivation layer over the encapsulant; andforming an external connector over the encapsulant, the forming theexternal connector comprising: applying a photoresist over the seedlayer; exposing the photoresist to a patterned energy source, thepatterned energy source having an in-focus area with a center point, thecenter point located below a surface of the photoresist facing towardsthe seed layer; developing the photoresist to form an opening; platingthe external connector into the opening, wherein after the plating theexternal connector the external connector has: a first portion with afirst width, the first portion extending through the passivation layer;a second portion with a second width larger than the first width, thesecond portion being located outside of the passivation layer; and atapered portion extending from the second portion to the first portion.16. The method of claim 15, wherein the tapered portion is located at atapered angle to a line, the line being parallel with a major surface ofthe encapsulant, the tapered angle being between about 10° and about85°.
 17. The method of claim 15, further comprising placing a solderball in physical contact with the external connector, the solder ballhaving an oval shape.
 18. The method of claim 17, further comprisingplacing a solder ball in physical contact with the external connector,the solder ball having a round shape.
 19. The method of claim 15,further comprising forming a seed layer over the passivation layer priorto the forming the external connector, wherein after forming theexternal connector the seed layer is patterned to have a straightsidewall perpendicular to a surface of the passivation layer.
 20. Themethod of claim 15, further comprising forming a redistribution layerover the encapsulant prior to the forming the external connector.